At the left, Skirrl sits pensively waiting for something to do. At the right, he is shown in one of 

 his early attempts at sawing. Skirrl was studied in comparison with Jimmie, another adult male mon- 

 key of the same species (Pithecus irus). Jimmie, vicious and never to be trusted, showed no interest 

 except in other monkeys, in his enemies, or food, whereas Skirrl was delighted with any object which 

 he might put to some mechanical use. He used a saw in as many ways as might a boy of four or five 

 years. He did not imitate the experimenter and learn to use it in the conventional manner, but pre- 

 ferred to work out his own methods. In the use of tools this monkey's behavior was so unusual and 

 individual that it amounted to genius 



One day Skirrl was noticed pounding a nail he had found in his cage. He was at once provided 

 with hammer, nails, and a board, and soon his skill, without tuition, in driving the nail into the board 

 more than equaled that of the unpracticed human being. Jimmie, on the other hand, would throw the 

 hammer into one corner of his cage, scatter the nails about, and try to tear the board to pieces with his 

 teeth. Observations of such extreme differences in individuality among animals are a spur to a more 

 profound study of man, to the end that there may be formulated for the future a science of human behavior 



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